There are 4 other players to consider that are not part of these numbers...

Ish Smith - has a non-guaranteed $788,872 - and I do not believe the Grizzlies will keep him.

Hamed Haddadi - has been extended the qualifying offer - of $2 million. I think the most likely thing to happen with Haddadi is that they offer him a few years at less than that (like 2 years for $3 million or something like that). If there is someone on the market they want and they need that money, they may just pull the offer completely (like they once did with Warrick).

Josh Selby - taken late in the draft so the $ will not be very significant. I think they pay him more than the minimum and try to sign him for multiple years rather than have him for 1. Like what they did with Sam Young, just for less money.

Marc Gasol - this is of course the most important player to talk about. The Grizzlies are not going to lose Gasol. He is a restricted FA, and they are willing to pay to keep him. My opinion is that it is going to cost about $11-12 million per year (going rate for young bigs) to keep him and they are willing to pay it.

So let's say Gasol gets $11 million in first year, and Selby gets $600,000...

That would mean the salary cap # goes to $63.7 million - and you would have 11 players on roster
Now, let's add in Haddadi at $2 million - now you are at $65.7 million and have 12 players on roster

The only number we have to worry about is the luxury tax - Heisley has proven he will spend up to it, but he is not going over that number. A good guess for the luxury tax is $70-71 million.

Some Grizzlies have bonuses (for All-Star game appearances and such) and if they are hit, those will count against the cap - so there has to be some wiggle room under the tax.

SIDE NOTE - They don't have the money or the ability to sign multi-year deals to keep Shane Battier. I wish they did.

That does not leave a bunch of money to add players to the roster, and you have to have at least 13 players. Being that the team has a window to really compete at the highest level, I think they may actually spend the remaining few million bucks all on one player, or just get rid of Haddadi and his salary and get 2 guys with about $5 million. At this point they would rather have one more good contributor and a short roster than just filling out the end of the bench with warm bodies.

They want to find at least one big guy that can play minutes behind Gasol. Some names to consider would be Josh McRoberts (who they tried to trade for last year), Jeff Foster, Joel Pryzbilla, or Dan Gadzuric. They are all big and could log minutes at center, and they are all unrestricted FA's.